Cylinder head for internal combustion engines



' E LEAPFELBIECKI'I 3,424,143

CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES 1 I Sheet Filed Aug, v11, 1967 -Jan.' 28,1969 "L.YAFFEILBECYKVY i 3,424,143

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CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Filed Aug. 11, 1967 Y Y Sheet 4 of 4 g2 F/G.6 /',f

//I6I 1 1g 32 j 27' 17 gg i 21 29 27 United States Patent 3,424,143 CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Ludwig Apfelbeck, Graz, Austria, assignor to Bayerlsche Motoren Werke Aktiengesellschaft, Munich, Germany Filed Aug. 11, 1967, Ser. No. 660,045

Claims priority, application Germany, Aug. 13, 1966,

B 88,485 U.S. Cl. 123191 Claims Int. Cl. F02b 23/00 ABSTRACT OF THE DESCLOSURE A cylinder head for a cylinder row of an internal combustion engine which includes per cylinder, an approximately hemispherically shaped combustion chamber, and four V-shaped radially suspended valves arranged in a cross-wise manner, of which two opposite valves form the inlet valves and the other two opposite valves form the outlet valves, whereby the planes determined by the axes of opposite valves subtend an angle of about 15 to 30 with the center longitudinal plane of the cylinder row as well as with the cross plane passing through the cylinder axes; the axes of the two inlet valves subtend a smaller V-angle than the axes of the two outlet valves, and/ or the inlet channels and the access bores for the spark plugs pass over into one another uninterruptedly in the direction of the longitudinal center plane of the cylinder row whereby the walls of the two inlet channels of a combustion space are directly connected with each other by way of the Walls of the access bore for the spark plug of this combustion space and the walls of an inlet channel of a combustion space is directly connected with the walls of the adjacent inlet channel of the next combustion space within the area of the longitudinal center plane of the cylinder row.

BACKGROUND OF THE INVENTION The present invention relates to a cylinder head for internal combustion engines with at least one cylinder row which contains, per cylinder, four cross-wise V-shaped radially suspended valves; namely, two mutually oppositely disposed larger inlet valves and two mutually oppositely disposed smaller outlet valves whereby the planes determined by the axes of the oppositely disposed valves subtend with the longitudinal center plane of the cylinder row and with the cross planes extending through the cylinder axes an angle of about 15 to 30 and whereby the inlet valves are disposed in the aforementioned rotated longitudinal planes.

Known in the prior art is a cylinder head of this type of construction (Austrian Patent 174,503) in which the pairs of identical valves disposed opposite one another in a cross-wise manner subtend identical V-angles. Even though this prior art type of construction already enabled a very compact construction with small cylinder spacings, ditficulties still exist with given cylinder spacings in connection with smaller cylinder units. Additionally, it is disadvantageous in connection with this prior art construction that the valve sizes cannot utilize and exploit in an optimum manner the spherically shaped surface of the combustion spaces whence there result undesirable reductions in the valve cross sections and therewith in the degree of filling and output of the engine. Finally, spatial difliculties also exist with the known prior art constructions with respect to constructing the cylinder head as unitary casting which additionally requires only covers and small attachment parts. Instead, a subdivision of the cylinder head into several castings is unavoidable in this prior art construction in order to support the cont-rol parts and assure the access for the machining.

3,424,143 Patented Jan. 28, 1969 SUMMARY OF THE INVENTION The purpose underlying the present invention resides in proposing features for a cylinder head of the aforementioned type of construction with maximum output which enables a unitary construction completely satisfactory as regards manufacturing requirements, involving few attachment parts and at the same time assuring maximum strength and rigidity.

The present invention solves the underlying problems by the features indicated hereinafter in the claims. By the application of smaller V-angles in connection with the inlet valves and of larger V-angles in connection with the outlet valves with simultaneous closest approach of all valves to the separating surface between cylinder head and cylinder, an optimum utilization of the spherical cornbustion space surface is achieved as well as the interengagement or interlacing of the valve stems and of the valve springs mounted thereon in the longitudinal direction of the cylinder row is simultaneously favored thereby because the outer lower valve stems and valve springs are arranged in a more flat manner and the inner, higher valve stems and valve springs come to stand up more steeply so that they receive a larger distance from each other or, with the same distance, the individual cylinders can be arranged more close to each other. Additionally, this enables with a given cylinder spacing also the use of valve springs with larger coil diameter. Finally, the relatively steep arrangement of the inlet valves favors a unitary construction of the cylinder head beacuse the valve stems of the inlet valves overlap each other less in the longitudinal direction of the cylinder row and therewith the valve stems or the imaginary extensions thereof project through the upper boundary surface of the cylinder head at a smaller distance from the cylinder axis whereby space for the bearing and securing places as well as reinforcing walls are gained between a respective inlet valve and the adjacent outlet valve of the next cylinder.

A longitudinal and cross webor rib-structure is achieved by the construction and arrangement of the walls of the inlet channels and of the cross walls connected therewith which adjoin the longitudinal outer walls, which produces a rigidity of the cylinder head completely satisfactory as regards the high pressures, forces and moments caused by the high filling degree of such an internal combustion engine. The cross walls are thereby utilized at the same time for the accommodation of the control and securing parts of the cylinder head.

In order that the inlet channels need not be limited in their cross section, the inlet channels are rotated or displaced by a larger angular amount out of the longitudinal center plane than the inlet valves. In this manner, between adjacent inlet channels of two neighboring combustion spaces, adequate sealing surfaces are available in the separating planes as well as cooling water passages are possible on the inside of the cylinder head which permit a uniform upper edge of the cooling water space over the entire cylinder head extension. Such cooling water passages are also provided between the bores for the cylinder head bolts and the walls of the inlet channels whereby a construction of the cooling water passages is assured which is free of any constriction in the dimension of its height.

Accordingly, it is an object of the present invention to provide a cylinder head for internal combustion engines which avoids by simple means the aforementioned shortcomings and drawbacks encountered with the prior art constructions.

Another object of the present invention resides in a cylinder head for internal combusion engines of the type described above which is particularly suitable for smaller cylinder units and which eliminates the difliculties encountered heretofore as regards the necessary spacing between the cylinders.

A further object of the present invention resides in a cylinder head for internal combusion engines which permits optimum utilization of the spherical surfaces of the combustion spaces.

Still a further object of the present invention resides in a cylinder head for internal combusion engines of the type described above which achieves all of the aforementioned aims and objects while simultaneously permitting a single unitary casting for the cylinder head.

Another object of the present invention resides in a unitary cylinder head for internal combustion engines of the type described above which requires only few covers and/ or attaching parts, yet permits ready accommodation and bearing support of the various actuating and control mechanisms necessary for the operation of the engine.

Still another object of the present invention resides in a cylinder head for internal combustion engines which can be readily machined and is easily accessible to the various parts notwithstanding the use of a unitary casting.

A further object of the present invention resides in a cylinder head for internal combustion engines which permits the use of valve springs with larger coil spring diameters.

A still further object of the present invention resides in a cylinder head for internal combustion engines which excels by a particularly appropriate construction of the cooling water passages.

These and further objects, features, and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of illustration only, one embodiment in accordance with the present invention, and wherein:

FIGURE 1 is a somewhat schematic plan view on the valve arrangement of a cylinder head according to the present invention for an internal combustion engine with an arrangement of the cylinders in a row and without cylider head wall parts:

FIGURE 2 is a somewhat schematic side elevational view of the valve arrangement of FIGURE 1;

FIGURE 3 is a plan view on the top side of the casting of a cylinder head of FIGURES 1 and 2 in accordance with the present invention;

FIGURE 4 is a cross-sectional view taken along line IVIV of FIGURE 3;

FIGURE 5 is a cross-sectional view taken along line V-V of FIGURE 3;

FIGURE 6 is a cross-sectional view taken along line V IVI of FIGURE 3; and

FIGURE 7 is a crosssectional view taken along line V-II-VII of FIGURE 4.

Referring now to the drawing wherein like reference numerals are used throughout the various views to designate like parts, reference numeral 1 designates the cylinder head for a cylinder row of four-cycle internal combustion engine provided with spherical combustion spaces 2 in which four valves 3 and 4 are arranged per combustion space; the valves 3 and 4 are disposed mutually opposite in a pair-wise manner, and more particularly two inlet valves 3 and two outlet valves 4 each. The axes 3' and 4' of the similar valve pairs 3 and 4 subtend with each other, respectively, a V-angle a. and 5 ('FIGS. 4 and 5). The V-an-gle a ('FIG. 4) of the inlet valves is smaller than the V-an'gle 5 (FIG. 5) of the outlet valves 4. Additionally, the pairs of valves 3 and 4 or the cross formed by the longitudinal and cross planes 5 and 6 (FIG. 1) determined by their axes 3 and 4' which is rectangular in plan views, is rotated by an angle 'y with respect to the longitudinal center plane 5 of the cylinder row and the cross planes 6 (FIG. 1). In this manner, the axes 3' and 4" and therewith the stems of the inlet and outlet valves 3 and 4, as well as the valve springs 3 and 4" overlap one another in the direction of the longitudinal center plane 5 as visible in particular from Figures 1 and 2. Due to the more steep arrangement of the inlet valves 3 and the more flat arrangement of the outlet valves 4 or of the axes 3 and 4' thereof as well as the valve springs 3" and 4" thereof, the overlap of these parts is favored so that with a given size of the valves and valve springs a particularly close approach of-the cylinder bores 7 is made possible, i.e., the cylinder bores 7 can be spaced particularly closely, or with a given distance of the cylinder bores 7, the use of valve springs 3" and 4" with sufiiciently large coil diameter is assured. Additionally, this construction of the V-angles a and ,B of the valves 3 and 4 together with an approximately equal approach or spacing of all the corresponding valve circumferential lines to the cylinder head sealing surface 1 and therewith to the boundary of the combustion space 2 enables an optimum utilization of the surfaces of the spherical combustion spaces 2 by the valves 3 and 4 whereby simultaneously, a favorable size ratio between the dimensions of the larger inlet valves 3 and of the smaller outlet valves 4 is achieved. Moreover, an arrangement of the spark plug 8 or of the spark plug thread 8 in the cylinder axis 9 and therewith in the center of the combustion space 2 results therefrom which is favorable from a manufacturing point of view as well as also for the operation of the combustion process.

The construction of the cylinder head 1 as unitary casting 10 provided only with simple covers and small attachment parts according to FIGURES 3 to 7 for the valve arrangement according to FIGURES 1 and 2 is realized as follows:

The cylinder head bottom side contains spherical combustion spaces 2 with valve apertures 13 and 14 and spark plug bores 8' (FIGS. 4 and 5), passage bores 12 for the cylinder head bolts and passage apertures 11 for the cooling water (FIGS. 3, 6 and 7). The valve axes 3' and 4 or the longitudinal and cross planes 5' and 6', determined by the same, form a rectangular cross which is rotated out of the longitudinal center plane 5 and the cross planes 6 by an angle 'y (FIG. 3). The valve axes 3 subtend a smaller V-angle a (FIG. 4) than the V-an-gle B (FIG. 5 of the valve axes 4'. Inlet channels 23 and outlet channels 24 adjoin the valve aperatures 13 and 14, respectively (FIGS. 4, 5 and 6). The inlet channels 23 extend approximately parallel to a respective cylinder head axis 9 up to the upper cylinder head boundary plane 1" of the cylinder head 10. The center axes 23 at the inlet channels 23 or the planes 5" determined thereby are rotated by a larger angle 7' with respect to the longitudinal center plane 5 of the cylinder row about the cylinder axes 9 than the angle 7 of the rotated longitudinal and cross planes 5 and 6 (FIGS. 3 and 7). Consequently, the inlet channels 23 of two adjacent combustion spaces 2 can receive thereby a large passage cross section without being arranged mutually too close. The outlet channels 24 extend approximately parallelly to the cross planes 6 along short paths toward the outside and terminate in connecting flanges 24' (FIG. 6) for the exhaust pipe lines whereby only a slight heating of the cylinder head casting by the hot exhaust gases is assured.

For purposes of cooling the walls of the combustion spaces 2 and of the outlet channels 24, cooling water spaces 21 are provided (FIGS. 4-7) which are connected by way of the apertures 11 with the cylinder water jacket (not shown). The cooling water spaces 21 of the individual combustion spaces 2 are in communication with each other (FIG. 7) by way of passage apertures 21' disposed between two adjacent inlet channels 23 and by way of further passage apertures 21" disposed between the inlet channels 23 and the bores 12 for the cylinder head bolts in such a manner that in the direction of the longitudinal center plane 5, no constrictions exist in the height of the cooling water passages. A collecting of air or water vapor bubbles is precluded thereby, and a uniform, flow of the cooling medium through the cooling water spaces 21 is assured without danger of local overheating.

Cross walls 19 (FIGS. 3 and 6) adjoin the walls 23" of the inlet channels 23 with the area above the cooling water spaces 21 and connect the walls 23" with the longitudinal outer walls 17 of the cylinder head. Additionally, the walls 23" of the inlet channels 23 of a respective combustion space 2 are connected with each by way of the walls 18 of the spark plug access bores 18 (FIGS. 3 and 6) whereas the walls 23" of the mutually adjoining inlet channels 23 of adjacent combustion spaces 2 pass over directly into one another within the area of their closest approach. A longitudinal and cross Web or cross rib connection is formed in this manner which imparts to the cylinder head casting 10 a particularly high bending and torsional rigidity. Chambers 20 (FIGS. 3, 4, and are formed by these longitudinal and cross web or rib connections which each accommodate a stem of an inlet valve 3 with the valve springs 3" of one combustion space 2 and a stem of an outlet valve 4 with valve spring 4" of an adjacent combustion space 2 together with the associated control parts such as cam shaft section, rocker arms, and the bearing elements thereof. The cross walls 19 are provided for the bearing support of these parts within the area of the upper cylinder head boundary plane 1" with open bearing half bores 22 for the cam shafts (FIG. 3) to be completed by hearing covers (not illus trated). For purposes of fastening the bearing covers, combined fitting and threaded bores 22 are provided. The cross walls 19 additionally contain bearing bores 25 with eyes 25' on both sides for bearing pins of rocker arms (not shown) as well as are provided with apertures 26 at the deepest places thereof for the unimpaired discharge of the lubricating oil (FIG. 6). The bores 12 (FIGS. 3, 6, and 7) for the cylinder head bolts bear against the cross walls 19 whose pipe-shaped walls 12' adjoin both the cross walls 19 as well as also the walls 23' of the inlet channels 23. Further bearing bores 27 (FIG. 3) which extend through bosses 27' at the longitudinal outer walls 17 and accommodate bearing bolts (not shown) for control rocker arms of the outlet valves 4, also terminate in the chambers 20.

Recesses 28 and 29 for the support of the inlet and outlet valve springs 3" and 4" are machined into the bottom 20' of the chambers 20 coaxial with the valve axes 3 and 4 which are adjoined by bores 28' and 29' for the valve guide means (FIGS. 3, 4, 5 and 7). Similarly, abutment surfaces 30 and securing threads 30 are arranged in the walls 23" of the inlet channels 23 within the chambers 20 which extend transversely to, respectively in the direction of the angle bisector 31 of the angle subtended by the valve axes 3' of the inlet valves 3 and the axes 23 of the inlet channels 23. These securing elements serve for the bearing support of rocker arms for the control of the inlet valves 3. The machining thereof is possible from the top side of the cylinder head casting 10. In order to enable also the machining of the recesses 29 and bores 29' from above as well as for the accessibility thereof during installation and service work, the chambers 20 are provided with apertures 32 in the longitudinal outer walls 17 adapted to be closed by covers (not shown). A continuous sealing flange 32' is provided for one cover each on a respective side.

While I have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible of numerous changes and modifications as known to a person skilled in the art, and I therefore do not wish to belimited to the details shown and described herein but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A cylinder head for a cylinder row of an internal combustion engine with approximately hemisphen'cally shaped combustion spaces and having four suspended valves per cylinder with the axes thereof arranged in a V-shape and consisting of two mutually oppositely disposed larger inlet valves and two mutually oppositely disposed outlet valves, the planes determined by the axes of opposite valves extending approximately through the cylinder axis and being disposed to one another approximately at right angle by subtending with the longitudinal center plane of the cylinder row and with the cross planes through the cylinder axes an angle of about 15 to 30, the inlet valves being disposed in the plane adjacent the longitudinal plane, and the axes of the two inlet valves subtending a smaller V-angle than the axes of the two outlet valves of a respective cylinder.

2. A cylinder head according to claim 1, wherein the smallest distances of the circumferential lines of the valve apertures to each other and from the separating surface between the cylinder head and cylinder are approximately equal with all valves.

3. A cylinder head according to claim 2, wherein the smallest distances of the circumferential lines of the valve apertures to each other and from the said separating surface are as small as possible with all valves.

4. A cylinder head for internal combustion engines, having at least one row of cylinders, four cross-wise, V-shaped radially suspended valves per cylinder consisting of two mutually opposite larger inlet valves and two mutually opposite smaller outlet valves, the planes determined by the axes of the opposite valves subtending with the longitudinal center plane of the cylinder row and with the cross planes extending through the cylinder axes an angle of about 15 to 30, inlet channel means and spark plug bore means extending approximately parallel to the cylinder axes, the wall means of said inlet channel means and spark plug bore means in the direction of the longitudinal center plane passing over into one another uninterruptedly, the Wall means of the two inlet channel means of one combustion space being directly connected with each other by way of the wall means of the spark plug bore means of the respective combustion space and the wall means of an inlet channel means of one combustion space being directly connected with the wall means of the next-adjacent inlet channel means of the next combustion space within the area of the longitudinal center plane of the cylinder row, cross wall means within the area of the greatest lateral projection of each inlet channel means adjoining the longitudinal outer wall means adjacent this place in such a manner that said wall means enclose chamber means which contain the stem and spring means of an inlet valve and of an outlet valve of two adjacent combustion spaces together with the associated control parts thereof.

5. A cylinder head according to claim 4, wherein the cross wall means accommodate the bearing places for the control parts including bearing bore means extending substantially parallelly to the center longitudinal plane for the camshafts and rocker arm bearing pins and bore means extending parallelly to the cylinder axes for the passage of the cylinder head bolts.

6. A cylinder head according to claim 5, wherein the planes determined by the axes of the inlet channel means are displaced by a larger angle from the longitudinal center plane of the cylinder row than the longitudinal planes determined by the axes of the inlet valves.

7. A cylinder head according to claim 6, wherein the axes of two opposite inlet valves su btend a smaller V-angle than the axes of two opposite outlet valves.

8. A cylinder head according to claim 7, wherein the smallest distance of the circumferential lines of the valve apertures in the cylinder head are approximately equal to each other and are as small as possible from the cylinder head-cylinder separating surface in connection with all valves.

9. A cylinder head according to claim 8, wherein the inlet channel means and the spark plug bore means are arranged substantially equi-axial to the cylinder axes.

10. A cylinder head according to claim 4, wherein the planes determined by the axes of the inlet channel means are displaced by a larger angle from the longitudinal center plane of the cylinder row than the longitudinal planes determined by the axes of the inlet valves.

11. A cylinder head according to claim 10, wherein the axes of two opposite inlet valves subtend a smaller V-angle than the axes of two opposite outlet valves.

12. A cylinder head according to claim 11, wherein the smallest distance of the circumferential lines of the valve apertures in the cylinder head are approximately equal to.

each other and are as small as possible from the cylinder head-cylinder separating surface in connection with all valves.

13. A cylinder head according to claim 4, wherein the axes of two opposite inlet valves subtend a smaller V-angle than the axes of two opposite outlet valves.

14. A cylinder head according to claim 4, wherein the smallest distance of the circumferential lines of the valve apertures in the cylinder head are approximately equal to each other and are as small as possible from the cylinder head-cylinder separating surface in connection with all valves.

15. A cylinder head according to claim 13, wherein the planes determined by the axes of the inlet channel means are displaced by a larger angle from the longitudinal center plane of the cylinder row than the longitudinal planes determined by the axes of the inlet valves.

References Cited FOREIGN PATENTS 174,503 4/1953 Austria.

WENDELL E. BURNS, Primary Examiner. 

